More specifically, the displaying device is preferably used in wall-mounted control apparatuses for home automation management systems.
These wall-mounted control apparatuses are usually connected to multiple domestic systems (heating, air conditioning, lighting, etc.) and allow the status of these systems to be displayed, using the displaying device, and managed.
Normally, a wall-mounted control apparatus is installed in a housing made (during construction) on a wall, for example of an apartment. More in detail, the control apparatus comprises a containment box which is inserted in the housing and which has an open side and a bottom wall opposite the open side. In other words, the containment box is substantially shaped to match the housing.
Moreover, the displaying device is connected to the box at the open side in such a way as to close the box.
According to the prior art, the displaying devices used comprise a transparent screen (normally made from glass) on which at least one graphical symbol is delineated. Moreover, the displaying devices comprise two electronic cards: a first electronic card, positioned in contact with a rear surface of the screen, and a second electronic card, connected to the first card and spaced from it. The first electronic card also comprises through holes each positioned at a respective graphical symbol of the screen.
The second electronic card is equipped with illumination bodies (preferably LEDs) each generating a beam of light in the direction of a respective hole of the first card.
More specifically, the beam of light, passing through a respective hole, illuminates an area of the screen making the symbols delineated in that area visible on the screen. More in detail, the graphical symbols are visible by observing the screen at a front visible surface (opposite the rear surface). Normally, the symbols are delineated on the screen by xerographics or adhesive films and they represent both word symbols (for example, “C.°”, “F.°”, “Off”, . . . ) and graphics (for example, a fan, a thermometer, . . . ).
In this context, moving an illumination body away from or towards a respective hole enlarges or narrows the illumination area on the screen.
For this reason, in order to illuminate sufficiently large graphical symbols (so as to guarantee a good visibility for the observer) it is necessary to have a sufficiently large area of illumination at the relative graphical symbol.
Therefore, the illumination bodies, and, consequently, the second card, must be adequately spaced from the holes.
More specifically, the distance between the two cards is preferably between 6 millimeters and 20 millimeters depending on the angle of emission of the beam of light by the illumination bodies.
For this reason, according to the pre-set distance between the cards, the displaying device defines an operating region on the screen which comprises all the illumination areas.
However, the prior art technique has several drawbacks.
In effect, the use of two electronic cards set apart from each other creates a predefined dimension in the box of the wall-mounted control equipment. Therefore, the illumination bodies must be positioned at a central area of the box in which the depth (measured from the open side to the bottom wall) is sufficient to house both the cards. More in detail, the depth of the box at the central area must be at least greater than the distance between the two electronic cards.
Consequently, the width of the operating region of the screen is limited by the width of the box (measured on a plane substantially parallel to the bottom wall) at the central area. In other words, the width of the operating region of the screen is substantially limited by the dimensions of the housing made on the wall.
Moreover, the use of two electronic cards set apart from each other creates a predefined dimension in the box of the wall-mounted control equipment thus reducing the volume available for other electronic devices (for example, thermometers, hygrometers, antennas, cables, etc.) which are positioned inside the box. This drawback is accentuated by the fact that the current control needs require the positioning inside the containment box of an ever greater number of electronic devices.